Etching solution application device for offset printing machines

ABSTRACT

An etching solution application device for use with offset printing machines of the type wherein master plates are fed automatically to the master cylinder and comprising an etching solution applying roller mounted for rotary motion and adapted to be brought into and out of pressing contact with the master cylinder in synchronism with the automatic mounting of the master plate on the master cylinder to apply the etching solution to the surface of the master plate. The etching solution application device is rendered inoperative and locked automatically as the applying roller is released from engagement with the master plate upon completion of the etching solution application operation.

United States Patent Kagari et a1.

14 1 Sept. 12, 1972 [72] Inventors: Yoshiharu Kagari;

Hirokawa; Toru Hasegawa, .all of Tokyo, Japan [73] Assignee: Ricoh Co.,Ltd., Tokyo, Japan 22 Filed: Sept. 4, 1970 211 Appl. No.: 69,568

[30] Foreign Application Priority Data Sept. 9, 1969 Japan ..44/7l486 [52] U.S. Cl ..l01/l42, 101/148 [51] Int. Cl. ..B41f 7/32, B4lf 7/40 [58] Field of Search ..l0l/136,l37,139,140,141, 101/142, 143-145, 148, 425

Koichi I 6/1970 Schinke etal. ..101/142 8/1971 Schinkeetal. ..l0l/l48 Primary Examiner-J. Reed Fisher Attorney-Henry T. Burke, Robert Scobey, Robert S. Dunham, P. E. Henninger, Lester W. Clark, Gerald L. Griffin, Thomas F. Moran, R. Bradlee and Christopher C. Dunham [57] ABSTRACT An etching solution application device for use with offset printing machines of the type wherein master plates are fed automatically to the master cylinder and comprising an etching solution applying roller mounted for rotary motion and adapted to be brought into and out of pressing contact with the master cylinder in synchronism with the automatic mounting of the master plate on the master cylinder to apply the etching solution to the surface of the master plate. The etching solution application device is rendered inoperative and locked automatically as the applying roller is released from engagement with the master plate upon completion of the etching solution application operation. a

3 Claims, 5 Drawing Figures PAIENTEDSEP 12 I972 SHEET 2 BF 2 ETCI-IING SOLUTION APPLICATION DEVICE FOR OFFSET PRINTING MACHINES BACKGROUND OF THE INVENTION This invention relates to etching solution application devices for offset printing machines and more particularly, to an automatic etching solution application device for use with offset printing machines of the type which are capable of automatically mounting a master plate on amaster cylinder, such device being'operative to automatically apply an ink-repellent etching solution to the master plate mounted on the-master cylinder.

In offset printing machines of the type which are capable of automatically mounting on a master cylinder, one after another, master plates piled in a stack on a master plate feed table, it is preferable that the operation of applying an ink-repellent etching solution to the master plate when mounted on the master cylinder be carried outautomatically.

Accordingly, this invention provides an automatic etching solution application device for positively applying an ink-repellent etching solution to a master plate by bringing an etching solution applying roller into contact with the master .plate when it is automatically SUMMARYOFTHE INVENTION The present invention embodies an apparatus for automatically applying etching solutions to master plates which areautomatically mounted on the master cylinder of an appropriate offset printing machine and comprises an applying roller which is mounted for movement between a solution transfer roller and the master plate which has associated operating and locking means for alternately pressing it against the respective roller and plate in performing the solution applying operation.

Additional objects as well as features and advantages of this invention will become evident from the description set forth hereinafter when considered in conjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of an etching solution application device comprising one embodiment of the present invention;

FIG. 2 is a fragmentary sectional view of the device of FIG. 1 showing an arrangement of the etching solution tank and rollers; 1

FIG. 3 is a fragmentary side view of the device of FIG. 1 showing an engaging arm and locking member associated with each other, and a solenoid connected to the locking member;

FIG. 4 is a side view of the device of FIG. 1 illustrating the manner of operation of the device; and

FIG. 5 is a perspective view of the device of FIG. I.

A DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will now be explained with reference to a preferred embodiment shown in the accompanying drawings. In FIG. 1, a fountain roller 1 is shown disposed above a master cylinder 4 of an offset printing machine, with a transfer roller 2 maintained in LII contact with the fountain roller 1 and both of which are rotatably supported by side plates (not shown) of the printing machine. The fountain roller 1 has a lower peripheral portion immersed in an etching solution contained in a tray portion 6a of an etching solution tank 6 as shown in FIG. 2. The etching solution tank 6 is removably attached to the printing machine. A reservoir 6c, communicating with the tray portion 6a through a metered opening 6b is formed integrally with the tank 6. The liquid level of the etching solution in the tray portion 6a is maintained at the same height as the upper edge of the opening 6b.

The transfer roller 2 is preferably made of rubber and there is provided. anetching solution applying roller 3, made by winding a cloth, sponge, belt or other liquid absorbing material 3a on a metallic roller, which is maintained in contact with the transfer roller 2. The applying roller 3 isfirmly secured to a shaft 8 rotatably supported by the two support arms 7a and 7b as shown in FIG. 5. A sprocket wheel-9 is attached to the end of the shaft 8 which is'supp ortedby the arm 7b. The arms and 7b are firmly secured at their bases to a shaft 10 which is rotatably'supported by immovable members (not shown) on the machine. Loosely mounted on the one end portion of the shaft 10 to which the base of the arm 7b is secured is a sleeve 1 1 having a gear 12,

sprocket wheel 13 and a serrated pulley l4 thereon.

The gear 12 is maintained in meshing engagement with a gear 15 secured to a shaft 2a of the transfer roller'2. A chain 16 (shown in dash-and-dot lines) is entrained about the sprocket wheels 9 and 13. A timing belt 20 is entrained about the pulley l4 and another pulley 17 through guide rollers 18 and 19. The pulley 17 is connected to a sprocket wheel 22 through an electro-magnetic clutch 21. Another chain24 (shown in dash-anddot lines) is entrained about the sprocket wheel 22 and another sprocket wheel 23 which is connected, together with a gear 25 mounted on the same shaft as the sprocket wheel 23, to a gear 28 through intermediate gears 26 and 27. The gear 28 is formed substantially integral with a blanket cylinder 5.

"Referring again to FIG. 1 the master cylinder 4 is adapted to rotate in the direction of the arrow 0, and the blanket cylinder 5 is adapted to rotate in the direction of the arrow b while maintained in contact with the master cylinder-4. Accordingly, the gear 28 also rotates in the direction of the arrow b.

Upon the actuation of a main switch (not shown), the master cylinder 4 and the blanket cylinder 5 rotate in the respective directions as aforementioned, and the gear 28 also rotates in the direction of the arrow b. The electromagnetic clutch 21 is engaged to connect the sprocket wheel 22 and pulley 17 for a predetermined interval of time after the main switch is closed by a timer (not shown). Thus, the sprocket wheel 9 and gear 15 cause the shaft 8 and shaft 2a to rotate in the directions of the arrow c and arrow d respectively during the predetermined time interval. Rotation of the shafts 8 and 2a in the indicated direetions causes the applying roller 3'to rotate in the direction of the arrow 0, the transfer roller 2 to rotate in the direction of the arrow d, and the fountain roller 1 to rotate in the direction of the arrow e while the applying roller 3 is maintained in pressing engagement with the transfer roller 2.

The etching solution is transferred from the fountain roller 1 to the liquid absorbing material layer 3a of the applying roller 3 through the transfer roller 2 while these rollers rotate, so that the layer 3a of the applying roller 3 is impregnated with the etching solution. As the aforesaid timer is rendered inoperative, the electromagnetic clutch 21 is disengaged, permitting only the gears 28, 27, 26 and and the sprocket wheels 23 and 22 to rotate. Since the liquid absorbing material layer 3a is soft and consequently has no sufficient rotation transmitting force the applying roller 3 and transfer roller 2 are both mechanically driven simultaneously to rotate. Thus, when the main switch is closed, a preparatory step for application of the etching solution is carried out for a predetermined interval of time.

As shown in FIGS. 3 and 5, an engaging arm 29 is firmly secured to the end of the shaft 10 to which the support arm 7b is secured. The engaging arm 29 has an engaging portion 29a formed at its forward end portion by bending. A hook 30a formed at the forward end of a locking member 30 loosely mounted on a shaft 31 is adapted to be engaged by the engaging portion 29a of the arm 29. Also loosely mounted on the shaft 31 is a lever 32 having one arm 32a which is connected by a shaft 35 to a connecting rod 34 pivotally connected at one end to an actuating bar 33a of a solenoid 33. A bant portion 30b is formed at an end portion of the locking member 30 opposite to the engaging portion 30a thereof with respect to the shaft 31. A tension spring 36 is mounted at one end on the bent portion 30b of the member 30 and at the other end on a pin 37 attached to the other arm of the lever 32, so that the locking member 30 is urged by the biasing force of the spring 36 to move in pivotal motion in a counterclockwise direction about the shaft 31.

When the parts are in the state shown in FIG. 1, with the solenoid 33 inoperative, the pin 37 is maintained in pressing engagement with a right shoulder 300 of the member 30 to restrain the locking member 30 against its movement in the counterclockwise direction as urged by the spring 36 and accordingly, the locking member 30 locks the engaging arm 29 in place. Now, as shown in FIGS. 1 and 5, an arm 38 is firmly secured at its base to the other end of the shaft 10 to which the support arm 7a is secured. A connecting rod 39 is pivotally connected at one end to the forward end of the arm 38 and at the other end to one arm 40a of a bellcrank 40 pivotally supported by a shaft 41 attached to a side plate (not shown) of the printing machine. A roller 42 is rotatably mounted at the end of the other arm 40b of the bellcrank 40 which is urged by the biasing force of a spring 43 to move in pivotal motion in a counterclockwise direction about the shaft 41. The bellcrank 40 urged in this way to move in pivotal motion in the counterclockwise direction in FIG. 1 urges the shaft 10 to rotate in the same direction, so that the applying roller 3 is urged to press against the master cylinder 4. The engaging arm 29 secured to the shaft 10 is also under the influence of the pivotal movement of the bellcrank 40 in the counterclockwise direction in FIG. 1, so that the arm 29 presses at its engaging portion 291: against the hook 30a of the locking member 30 which is restrained against pivotal movement in the counterclockwise direction and maintained in the locking position by the pin 37.

After the main switch has been closed and the preparatory step for etching solution application has been carried out, a start button is depressed. Depression of the start button causes a master plate feed roller 44 (FIG. 1) to rotate in the direction of the arrow f and deliver to a guide plate 46 the uppermost master plate of a pile of master plates 0 resting on a master plate tray 45. At the same time, the electromagnetic clutch 21 (FIG. 5) is actuated again and controlled by the timer as aforesaid so as to cause the applying roller 3 and transfer roller 2 to rotate in the manner of the etching solution applying operation.

Delivery rollers 47 and 48 pressing against each other during rotation are provided in an intermediate position along the length of the guide plate 46, and an actuator 49a of a switch 49 is provided in the vicinity of the rollers 47 and 48. As a master plate 0, fed by the feed roller 44, is gripped by the delivery rollers 47 and 48, the master plate 0 moves the actuator 49a and closes the switch 49. The switch 49 is included in a power supply circuit for the solenoid 33, so that the solenoid 33 is energized by theclosing of the switch 49. It is possible to provide an indication that the master plate has been fed to the master cylinder by also connecting the switch 49 to an indication lamp (not shown) or the like. Energization of the solenoid 33 causes the actuating bar 330 to pull the connecting rod 34 to the right in FIG. 1, so that the lever 32 moves in pivotal motion in the counterclockwise direction about the shaft'3l. The counterclockwise movement of the lever 32 causes the pin 37 to be released from engagement with the shoulder 300 of the locking member 30 as shown in FIG. 3, thereby releasing the locking member 30 and permitting the same to move in pivotal motion in the counterclockwise direction about the shaft 31 by virtue of the action of the biasing force of the spring 36. However, the engaging portion 29a of the engaging arm 29 is maintained in pressing engagement with the hook 30a of the locking member as aforesaid. The frictional dragging between the engaging portion 290 and the hook 30a is set to be greater than the biasing force of the spring 36, so that the engaging arm 29 is still locked in position by the locking member 30.

It is for the purpose of bringing the applying roller 3 into pressing engagement with the master cylinder 4 simultaneously as the master plate 0 is mounted on the latter as subsequently to be described that the engaging arm 29 is not unlocked directly as a result of energization of the solenoid 33. Thus, the locking member 30 is only released from engagement with the pin 37 of the lever 32 as a result of energization of the solenoid 33 till the applying roller 3 is brought into contact with the master cylinder 4.

Attached to the shaft 5a of the blanket cylinder 5 (FIG. 1) is a cam 50 having a protuberance 50a on its outer peripheral portion which is adapted to move the roller 42 upwardly against the biasing force of the spring 43 simultaneously as the leading end of the master plate 0 is gripped by master plate grip pawls 4b on the master cylinder 4 as the cam 50 rotates in the direction of the arrow 12 together with the blanket cylinder 5. If the roller 42 moves upwardly, then the bellcrank 40 moves in pivotal motion in a clockwise direction about the shaft 41, and pivotal movement of the bellcrank 40 is transmitted to the shaft 10 through the connecting rod 39 and arm 38 to cause the shaft to rotate in the same direction as the pivotal movement of the bellcrank 40 about the shaft 41. Rotation of the shaft 10 in the clockwise direction causes the engaging arm 29 disposed in a position shown in FIG. 3 to move in pivotal motion in the clockwise direction about the shaft l0, with a result that the engaging portion 29a of the engaging arm 29 is releasedfrom pressing engagement withthe hook 30a of the locking member 30. Since the lever32 has moved in pivotal motion in the counterclockwise direction about the shaft 31 upon energization of the solenoid 33 as aforesaid, the locking member 30 is moved in pivotal motion in the counterclockwise direction about the shaft 31 by the biasing force of the spring 36 till the shoulder 30c abuts against the pin 37.

Upon completion of the upward movement of the roller 42 caused by the protuberance 50a of the cam 50, the engaging ann 29 is completely released from engagement with the locking member 30 as aforesaid, so that the I shaft 10 is then rotated in thecounterclockwise direction by the biasing forceof the spring 43. Asa result, the support arms 7a.and 7b move in pivotal motion in the-same direction as the counterclockwise rotation of the shaft 10, thereby releasing the applying roller 3 from engagement with the transfer roller 2 and bringing the same into pressing engagement with the master cylinder 4 as shown in FIG. 4. At this time, the master plate 0 has its leading .and gripped by grip pawls 4b provided in a recess 4a on the master cylinder 4. Accordingly, .theapplying roller3 rotating in thedirection of the arrow b is brought into pressing engagement with the leading end of the master plate 0 on the master cylinder 4, so'that the etching solution impregnating the layer 30 of the roller 3 is applied to the surface of the master plate 0 rotating in the direction of the arrow a together with the master cylinder 4. Since the master cylinder 4 and the applying roller 3 are rotating in opposite directions, they press against each other as the etching solution is applied to the master plate 0. The cam 50 is constructed such that when the applyingroller 3 is maintained in pressing contact with the master cylinder 4, the outer peripheral surface-of the cam 50, except for the protuberance 50a does not move the roller 42 upwardly. The master cylinder 4 and applying roller 3 rotate several times while they are maintained in pressing engagement with each other so that the etching solution may be applied thoroughly to the master plate 0. Thus, during the etching solution application operation, the recess 4a passes the applying roller 3 several times. Since the roller 42 is moved upwardly by the protuberance 50a of the cam 50 each time the recess 4a passes the applying roller 3, the applying roller 3 is moved upwardly and prevented from dropping into the recess 4a.

During the etching solution application operation the cam 50 rotates several times and the protuberance 50a moves the roller 42 upwardly several times, causing the engaging arm 29 to move in pivotal motion toward the locking member 30. The solenoid 33 is controlled by the timer such that the connecting rod 34 remains pulled by the solenoid 33 tothe right in FIG. 1 during the etching solution application operation thereby maintaining the locking member 30 in nonlocking .position. Therefore, the engaging arm 29 is not engaged and locked in position by the locking member 30 in spite of its pivotal movements.

As the etching solution application operation is completed, the solenoid 33 is de-energized and the connecting rod 34 is moved to the left in FIG. 1. This causes the lever 32 to move in pivotal motion in the clockwise direction about the shaft 31, so that the pin 37 engages and moves the shoulder 30c of the locking member 30 downward. Accordingly, the locking member30 is brought to the locking position shown in FIG. 1 and held inthis position by the pin 37. With the locking member 30 in this position, the engaging portion 29a of the engaging arm 29 which is moved in pivotal motion in the clockwise direction about the shaft 10 in conjunction with the upward movement of the roller 42 caused by the protuberance 50a of the cam 50 is brought into pressing engagement with the hook 30a of the locking member 30 when the engaging arm 29 moves in the counterclockwise direction in its return movement. Thus, the engaging arm 29 is locked clutch 21 is again rendered inoperative preparatory to beginning the entire operation over again.

From the foregoing description, it will be appreciated that the etching solution application device I according to this invention is simple in construction and reliable in performance, contributing greatly to full automation-of the offset printing machine.

Although the drawings and description relate to one embodiment of this invention, it should be understood that there is no intention to limit the invention to the disclosed construction and instead .it is intended that the invention should extend to all alternative embodiments and constructions falling within the scope of the following claims.

What is claimed is:

1. An etching solution application device for offset printing machines or the like of the type having:

a. a master cylinder;

b. means for feeding master plates to said master cylinder and switch means for producing a signal indicating each such feeding;

c. roller means for supplying etching solution from a reservoir; and

d. a solution applying roller for receiving etching solution from said supplying roller means and applying it to the surface of said master plates; wherein the improvement comprises:

e. means for pivotally mounting said applying roller for movement into and out of engagement with the surfaces of said master plates, said mounting means including:

i. a rotatable support shaft;

ii. support arms engaging the opposite ends of said applying roller and mounted on said support shaft;

iii. means at one end of said support shaft urging it to rotate so as to press said applying roller into engagement with the surface of a master plate;

and f. locking means for holding said applying roller in an out-of-engagement position and for releasing said applying roller, in response to a signal from said switch means indicating the feeding of a master plate to said master cylinder, to engage the surface thereof, said locking means including;

iv. a locking member;

v. means at the opposite end of said support shaft 10 from said urging means cooperating with said locking member to hold the support shaft against rotation by said urging means;

vi. means actuated by said indicative signal from said switch means for releasing said locking master plate under the action of said urging means, said means for releasing said cooperating means including:

1. a cam means mounted for rotation in synchronism with said master cylinder; and

2. follower means riding on said cam means and operatively connected to said support shaft to rotate it against the action of said urging means in accordance with the action of said cam means thereon.

2. A device as in claim 1 wherein said locking means holds said applying roller in engagement with said supplying roller means in the out-of-engagement position.

3. A device as in claim 1 including:

h. means for locking said locking member after the members; and

vii. means rotating with said master cylinder for releasing said cooperating means from cooperation with said locking member upon the release of said locking member thereby permitting said applying roller to engage the surface of said application of etching solution to a master plate; and

'. means on said locking member for holding said cooperating means upon the locking of said locking member. 

1. An etching solution application device for offset printing machines or the like of the type having: a. a master cylinder; b. means for feeding master plates to said master cylinder and switch means for producing a signal indicating each such feeding; c. roller means for supplying etching solution from a reservoir; and d. a solution applying roller for receiving etching solution from said supplying roller means and applying it to the surface of said master plates; wherein the improvement comprises: e. means for pivotally mounting said applying roller for movement into and out of engagement with the surfaces of said master plates, said mounting means including: i. a rotatable support shaft; ii. support arms engaging the opposite ends of said applying roller and mounted on said support shaft; iii. means at one end of said support shaft urging it to rotate so as to press said applying roller into engagement with the surface of a master plate; and f. locking means for holding said applying roller in an out-ofengagement position and for releasing said applying roller, in response to a signal from said switch means indicating the feeding of a master plate to said master cylinder, to engage the surface thereof, said locking means including; iv. a locking member; v. means at the opposite end of said support shaft from said urging means cooperating with said locking member to hold the support shaft against rotation by said urging means; vi. means actuated by said indicative signal from said switch means for releasing said locking members; and vii. means rotating with said master cylinder for releasing said cooperating means from cooperation with said locking member upon the release of said locking member thereby permitting said applying roller to engage the surface of said master plate under the action of said urging means, said means for releasing said cooperating means including:
 1. a cam means mounted for rotation in synchronism with said master cylinder; and
 2. follower means riding on said cam means and operatively connected to said support shaft to rotate it against the action of said urging means in accordance with the action of said cam means thereon.
 2. follower means riding on said cam means and operatively connected to said support shaft to rotate it against the action of said urging means in accordance with the action of said cam means thereon.
 2. A device as in claim 1 wherein said locking means holds said applying roller in engagement with said supplying roller means in the out-of-engagement position.
 3. A device as in claim 1 including: h. means for locking said locking member after the application of etching solution to a master plate; and j. means on said locking member for holding said cooperating means upon the locking of said locking member. 